2020 Jeep Wrangler Diesel P0299 and P049B codes

[crimsontidewins]

2020 Wrangler Sahara with 93000 miles. Purchased at the first of the year, 2024, and 2 weeks ago the display gave me 'service throttle control module' + 'service stability control system', and disabled the cruise control.
Codes thrown P0299 and P049B, they are and were the only active codes. I had 2 stored codes P1DB6 and C121C but they, as of yet, have not reappeared after clearing them. The Jeep runs OK just without any Turbo boost thus no get up and go but drivable.

Inspected all the turbo lines in and out, inspected the EGR return tube from the exhaust back up to EGR. Pulled MAP sensor and cleaned, pulled EGR diffuser tube and cleaned.
Cleared the codes, have cleared them several times, all with the same results. Jeep runs normally for 5 to 10 mins with the turbo spooling up and everything running as it should. Even when really getting on the throttle it runs as it should, then the display gives me the 'service throttle control module' + 'service stability control system'. The cruise control disabled and no turbo boost. Same as before the code reset with the same codes thrown again. (P0299 and P049B)

Right now I am thinking the P1DB6 and the C121C are outliers because they have not reappeared.

Hoping someone can give me a direction to continue to look.

Thanks,

Sponsored

 

[rharr]

If you are asking about codes, you should probably include the text associated with them.

Other then that it's a wild goose hunt to focus on a system.

Have you checked the harness that runs right next to the egr flange? It is a known issue that the EGR flange SS gasket can cut into the harness and screw with a lot of transmission and control systems.

Stability control can be a lot of things. I got similar stability MIL stuff and it involved me adding some slack to the rear LF wheel speed sensor, it was getting tweaked and screwing with connectivity.

 

[crimsontidewins]

If you are asking about codes, you should probably include the text associated with them.

Other then that it's a wild goose hunt to focus on a system.

Have you checked the harness that runs right next to the egr flange? It is a known issue that the EGR flange SS gasket can cut into the harness and screw with a lot of transmission and control systems.

Stability control can be a lot of things. I got similar stability MIL stuff and it involved me adding some slack to the rear LF wheel speed sensor, it was getting tweaked and screwing with connectivity.

P0299 Low Turbo Boost
P049B EGR B flow insuffieint detected

 

[22EcoDs]

Don't you still have the 5 year 100k mile drivetrain warranty? Id look at the harness by the exhaust if you haven't already. That's known to chafe on the diesel gladiators.

 

[crimsontidewins]

Don't you still have the 5 year 100k mile drivetrain warranty? Id look at the harness by the exhaust if you haven't already. That's known to chafe on the diesel gladiators.

No, no warranty that I know of, at least when I ran a check. Yes, I looked at the harness.
Thanks

 

[crimsontidewins]

2020 Wrangler Sahara with 93000 miles. Purchased at the first of the year, 2024, and 2 weeks ago the display gave me 'service throttle control module' + 'service stability control system', and disabled the cruise control.
Codes thrown P0299 and P049B, they are and were the only active codes. I had 2 stored codes P1DB6 and C121C but they, as of yet, have not reappeared after clearing them. The Jeep runs OK just without any Turbo boost thus no get up and go but drivable.

Inspected all the turbo lines in and out, inspected the EGR return tube from the exhaust back up to EGR. Pulled MAP sensor and cleaned, pulled EGR diffuser tube and cleaned.
Cleared the codes, have cleared them several times, all with the same results. Jeep runs normally for 5 to 10 mins with the turbo spooling up and everything running as it should. Even when really getting on the throttle it runs as it should, then the display gives me the 'service throttle control module' + 'service stability control system'. The cruise control disabled and no turbo boost. Same as before the code reset with the same codes thrown again. (P0299 and P049B)

Right now I am thinking the P1DB6 and the C121C are outliers because they have not reappeared.

Hoping someone can give me a direction to continue to look.

Thanks,

An update: I have not been able to devote as much time to troubleshooting this as I would like due to life issues, wife hurt her back and keeping grandkids. With that understood....
I ran another diagnostics check and cleared codes and let them reappear and reran the Diagnostic Check and got the same P0299 and P049B codes with an additional code P2227 (DASM Driver Assistance System Module; ABS disabled ECU). Ran through every ABS test that I could do including pump test, valve tests etc. Also, checked the speed reading of all four ABS sensors. Everything check out.

So, I am thinking that it's either a ABS module gone bad (the electronics) and no I have not gotten a ABS light or the PCM has a fault and is going bad.

If anyone has any other ideas, please let me know.

Thanks

 

[rharr]

or you have a short somewhere, it's not always the module, the module only reports on signals it gets.

 

[crimsontidewins]

Ok, here's another update: As I am getting to know and understand my new Scan/Diagnostic tool I found that the C2227 code (ABS disabled ECU) is under the DASM (Driver Assistance System Module) with the C121C code (Torque request denied) under the ABS Module. I deleted the Aux Battery by pulling the 42 fuse and disconnecting the ground from the Aux Battery. Cleared all the codes and started fresh.

Had no change at all. Jeep drove as it should with the turbo boosting etc. then it throw the 'service throttle control' and others as previously described.

Reran diagnostics and get the P0299 and P049B along with the C2227 and C121C codes.

I am still leaning to the ABS Module but I still can't grasp not having an "ABS" light. Also, as previously noted I have run through all the ABS test that my Autel MaxiCom MK900 will do with not one failure. That's what got me puzzled and scratching my head.

I am continuing my search and appreciate any ideas, thoughts or suggestions.

Blessings

 

[wildtaco]

Ok, here's another update: As I am getting to know and understand my new Scan/Diagnostic tool I found that the C2227 code (ABS disabled ECU) is under the DASM (Driver Assistance System Module) with the C121C code (Torque request denied) under the ABS Module. I deleted the Aux Battery by pulling the 42 fuse and disconnecting the ground from the Aux Battery. Cleared all the codes and started fresh.

Had no change at all. Jeep drove as it should with the turbo boosting etc. then it throw the 'service throttle control' and others as previously described.

Reran diagnostics and get the P0299 and P049B along with the C2227 and C121C codes.

I am still leaning to the ABS Module but I still can't grasp not having an "ABS" light. Also, as previously noted I have run through all the ABS test that my Autel MaxiCom MK900 will do with not one failure. That's what got me puzzled and scratching my head.

I am continuing my search and appreciate any ideas, thoughts or suggestions.

Blessings

It will have something to do with the emissions system, possibly being clogged/cracked. I've had both P049B-00 and P0299-00 along with a couple others, and it ended up being a cracked DPF. Truck kept going into limp mode. Dealer replaced it and has been fine since.

The C121C-00 code is your Jeep going into limp mode. This is a symptom of your problem, not the root cause.

 

[crimsontidewins]

It will have something to do with the emissions system, possibly being clogged/cracked. I've had both P049B-00 and P0299-00 along with a couple others, and it ended up being a cracked DPF. Truck kept going into limp mode. Dealer replaced it and has been fine since.

The C121C-00 code is your Jeep going into limp mode. This is a symptom of your problem, not the root cause.

I totally agree with C121C is a symptom along with the P0299 and P049B. I have inspected exhaust system, twice and didn't see any indication of a leak. (I have a lift so it isn't that difficult for me to do that) If I could verify that the emissions system was the cause, well there's a fix coming for that. What about the C2227 code?

Thanks for the input.

 

[wildtaco]

I totally agree with C121C is a symptom along with the P0299 and P049B. I have inspected exhaust system, twice and didn't see any indication of a leak. (I have a lift so it isn't that difficult for me to do that) If I could verify that the emissions system was the cause, well there's a fix coming for that. What about the C2227 code?

Thanks for the input.

I don't have anything on the C2227 code.

A quick check you can do is inspect the inside of your tailpipe for soot. That would indicate that DPF is cracked, allowing soot to blow through.

 

[DylanM]

Your C2227 code is just another symptom, not to be worried about at this point. It will set any time you have an active ABS fault code, which in your case is the C121C.

 

[DylanM]

I am still leaning to the ABS Module but I still can't grasp not having an "ABS" light. Also, as previously noted I have run through all the ABS test that my Autel MaxiCom MK900 will do with not one failure. That's what got me puzzled and scratching my head.

The C121C fault won't cause the ABS warning light to illuminate, just the ESC light. What's causing the C121C code to kick out are your powertrain fault codes which are limiting the engine output. Adding this info to the fact the ABS module is passing all your scanner tests, it's safe to say at this point that the module is fine.

The driving cause behind the various warning lights and codes then is powertrain related: your P0299 and P049B codes. Looking further into what can cause those codes, we see that the P0299 will kick out when there are active EGR fault codes present, so the focus should be on solving the P049B first.

 

[crimsontidewins]

The C121C fault won't cause the ABS warning light to illuminate, just the ESC light. What's causing the C121C code to kick out are your powertrain fault codes which are limiting the engine output. Adding this info to the fact the ABS module is passing all your scanner tests, it's safe to say at this point that the module is fine.

The driving cause behind the various warning lights and codes then is powertrain related: your P0299 and P049B codes. Looking further into what can cause those codes, we see that the P0299 will kick out when there are active EGR fault codes present, so the focus should be on solving the P049B first.

Great information, Thanks.
Question, why is it that after resetting the codes it runs normally for a short time? Is it taking that time to see the faults? Thanks in advance for the answers.

I'll have to check the LP EGR Differential pressure sensor, Not sure how to check the cooler. I have checked the turbocharger inlet and outlets for leaks. Will check the MAF sensor. The EGR valve checked via the Diagnostic tool, it operated as commanded without fault.

Thanks again for the info and advice.

 

[crimsontidewins]

The C121C fault won't cause the ABS warning light to illuminate, just the ESC light. What's causing the C121C code to kick out are your powertrain fault codes which are limiting the engine output. Adding this info to the fact the ABS module is passing all your scanner tests, it's safe to say at this point that the module is fine.

The driving cause behind the various warning lights and codes then is powertrain related: your P0299 and P049B codes. Looking further into what can cause those codes, we see that the P0299 will kick out when there are active EGR fault codes present, so the focus should be on solving the P049B first.

Also, do you think it's the EGR system? thanks

Sponsored